This invention relates to a liquid cooling arrangement for an engine and more particularly to an improved gasket and sealing arrangement between two members of a liquid cooled internal combustion engine.
As is well known, internal combustion engines and particularly liquid cooled engines have a number of mating parts with sealing gaskets interposed therebetween. When the engine is water cooled, these sealing gaskets perform the function of sealing the water passages so that water may flow from the cooling jacket of one member to the cooling jacket of another member while providing a seal around the flow area.
Frequently, the opening of the cooling jacket in the sealing surface of one member does not line up completely with the opening of the cooling jacket formed in the facing surface of the other member. For example, it is commonly the case that where the cylinder head and cylinder block meet, the cylinder block cooling jacket has an opening in the surface that faces the cylinder head which is substantially larger than the corresponding flow opening that communicates the cylinder head cooling jacket with the cylinder block cooling jacket.
This gives rise to a problem which may be best understood by reference to FIG. 1 that shows a sealing arrangement of the type commonly found in prior art constructions between a cylinder block, indicated generally by the reference numeral 11 and a cylinder head indicated generally by the reference numeral 12 with a sealing gasket 13 being interposed between facing surfaces 14 and 15 of the cylinder block 11 and cylinder head 12, respectively. As may be seen, the cylinder block 11 has a cooling jacket 16 which has an opening 17 in its surface 14. The cylinder head 12 has a cooling jacket shown partially at 18 and which has an opening 19 in its sealing face 15 which is substantially smaller than the cylinder block cooling jacket opening 17.
As is common practice, however, the interposed gasket 13 has an opening 21 in it which is slightly larger than the cylinder head opening 19 but substantially smaller than the cylinder block opening 17. This means that there is a surface area between the cylinder head gasket 13 and the cylinder head gasket surface 15 that is not backed up by a corresponding surface of the cylinder block 11. As a result, liquid coolant can become trapped between these facing surfaces and remain there even when the cooling jacket of the engine is drained of water. This can present problems, particularly when the engine is utilized in such applications as outboard motors wherein the cooling jacket is frequently drained of water when the outboard motor is taken out of use or even when it is tilted up out of the water and still attached to the transom of a watercraft. The resulting water entrapment can cause corrosion, particularly when the outboard motor has experienced salt water through operation in a marine environment.
With the discontinuation of the use of asbestos as a gasket material and the substitution of metal such as stainless steel for the gasket material, these problems become even more acute.
It is, therefore a principal object of this invention to provide an improved gasket and sealing arrangement for a water cooled engine.
It is a further object of this invention to provide an improved gasket and sealing arrangement for an engine wherein areas that may exist between the facing surface of one of the engine members around an opening that is not backed up by engagement with a facing surface of the other member due to differences in the size and location of their respective openings may be drained easily of water that may be otherwise entrapped between the gasket and the surface of the one member.